They can detain me indefinitely if they want, I will never give my pin to border security. I'm not going to bend to this bullshit by not carrying a phone.
I suspect your tune may change when you find yourself in indefinite detention, have missed your connecting flight, and your family/friend/spouse/boss has called said phone and been told by CBP that you're refusing to comply with an investigation.
If my peers find it acceptable that I am detained indefinitely simply for not unlocking my phone, then throw away the key because all is lost.